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Spastic cocontraction in hemiparesis: Effects of botulinum toxin

Authors

  • Maria Vinti PT, MSc,

    Corresponding author
    1. Arts et Métiers ParisTech, Laboratoire de Biomécanique, Paris, France
    2. Université Paris Est Créteil (UPEC), Créteil, France
    3. AP-HP, Service de Médecine Physique et de Réadaptation, Unité de Neurorééducation, Groupe Hospitalier Henri Mondor, 50 avenue du Maréchal de Lattre de Tassigny, Créteil F-94010, France
    • Arts et Métiers ParisTech, Laboratoire de Biomécanique, Paris, France
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  • Filomena Costantino MSc,

    1. Arts et Métiers ParisTech, Laboratoire de Biomécanique, Paris, France
    2. Université Paris Est Créteil (UPEC), Créteil, France
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  • Nicolas Bayle MD,

    1. Arts et Métiers ParisTech, Laboratoire de Biomécanique, Paris, France
    2. Université Paris Est Créteil (UPEC), Créteil, France
    3. AP-HP, Service de Médecine Physique et de Réadaptation, Unité de Neurorééducation, Groupe Hospitalier Henri Mondor, 50 avenue du Maréchal de Lattre de Tassigny, Créteil F-94010, France
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  • David M. Simpson MD,

    1. Department of Neurology, Mount Sinai School of Medicine, New York, New York, USA
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  • Donald J. Weisz PhD,

    1. Department of Neurosurgery, Mount Sinai School of Medicine, New York, New York, USA
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  • Jean-Michel Gracies MD, PhD

    1. Arts et Métiers ParisTech, Laboratoire de Biomécanique, Paris, France
    2. Université Paris Est Créteil (UPEC), Créteil, France
    3. AP-HP, Service de Médecine Physique et de Réadaptation, Unité de Neurorééducation, Groupe Hospitalier Henri Mondor, 50 avenue du Maréchal de Lattre de Tassigny, Créteil F-94010, France
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Abstract

Introduction: In this study of spastic hemiparesis we evaluated cocontraction during sustained agonist/antagonist efforts, before and after botulinum toxin (BoNT) injection in 1 agonist. Methods: Nineteen hemiparetic subjects performed maximal isometric elbow flexion/extension efforts with the elbow at 100° (extensors stretched). Using flexor and extensor surface electromyography we calculated agonist recruitment/cocontraction indices from 500-ms peak voluntary agonist recruitment, before and 1 month after onabotulinumtoxinA injection (160 U) into biceps brachii. Results: Before injection, agonist recruitment and cocontraction indices were higher in extensors than flexors [0.74 ± 0.15 vs. 0.59 ± 0.10 (P < 0.01) and 0.43 ± 0.25 vs. 0.25 ± 0.13 (P < 0.05), respectively]. Biceps injection decreased extensor cocontraction index (−35%, P < 0.05) while increasing flexor agonist recruitment and cocontraction indices. Conclusions: In spastic hemiparesis, stretch may facilitate agonist recruitment and spastic cocontraction. In the non-injected antagonist, cocontraction may be reduced by enhanced reciprocal inhibition from a more relaxed, and therefore stretched, agonist, or through decreased recurrent inhibition from the injected muscle. Muscle Nerve, 2012

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